Some vehicles are provided with a torque limiter for preventing components such as a transmission from being damaged or broken by excessive torque transmitted thereto from an engine. The torque limiter is normally disposed between the engine and the transmission for limiting torque transmitted thereto. In the torque limiter, for instance, at least one friction facing is interposed and held between a pair of plates at a predetermined holding force. Further, the input side of the torque limiter is coupled to engine-side members (e.g., a flywheel), while the output side of the torque limiter is coupled to transmission-side components (e.g., an input shaft).
The torque limiter of the aforementioned type includes a drive plate, a transmission torque limiting part, a driven-side member and a damper mechanism (see e.g., Patent Literature 1). The drive plate includes a friction coupling portion on the radial outer portion thereof. The transmission torque limiting part has a structure that the friction coupling portion of the drive plate is interposed and held between a pair of plates at a predetermined holding force. The driven-side member is coupled to an input shaft of a transmission. The damper mechanism is disposed among the aforementioned components. In the torque limiter, the paired plates that the friction coupling portion is interposed and held therebetween (or a damper cover disposed radial outwards of the friction coupling portion) are coupled to the flywheel.
In the torque limiter, engine torque is transmitted from the flywheel to the drive plate via the friction coupling portion and is further transmitted to the driven-side member and the input shaft of the transmission via the damper mechanism. When the engine torque then exceeds a predetermined level, slippage occurs between the plate and the friction coupling portion. Excess of the torque, exceeding the limit imposed by the transmission torque limiting part, is accordingly prevented from being transmitted to the transmission. Therefore, the transmission can be prevented from being damaged or broken by the excessive torque.
Japan Laid-open Patent Application Publication No. JP-A-2006-017226 (Patent Literature) is an example of the related art.